In a drug delivery, crystalline forms having useful and outstanding chemical and/or physical properties are desired.
The patent document 1 describes that a 6,7-unsaturated-7-carbamoyl morphinan derivative represented by the following formula:
is useful as a therapeutic and/or prophylactic agent of the emesis and/or constipation. Although the following compound (I-284):
is disclosed in a form of free salt in Examples of the patent, an acid addition salt and/or a solvate are not specifically disclosed. Further, there is no description at all about the crystal thereof.
As a method for preparing the 6,7-unsaturated-7-carbamoyl morphinan derivative, all that disclosed is a method for synthesizing a corresponding 7-carbamoyl derivative from 7-carboxy derivative as shown by the following formula:
